KR100470228B1 - Carrier Head for Chemical Mechanical Polishing - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carrier head of a chemical mechanical polishing apparatus for polishing and planarizing a semiconductor wafer, the main configuration comprising: a carrier housing; A wafer support assembly disposed under the carrier housing and capable of vertical lifting and having an adjustment chamber therein configured to adsorb or remove the wafer by internal pressure adjustment; A retainer ring installed at an outer side of the wafer support assembly and capable of vertical movement separately from the wafer support assembly, the retainer ring forming a receiving space of the wafer to prevent the wafer from being separated from the lower surface of the wafer support assembly; A conditioner ring installed outside the retainer ring; It is formed in the space defined by the carrier housing and the body and comprises a loading chamber for controlling the vertical position of the wafer support assembly, by the above configuration to adsorb the wafer using a direct vacuum method to the carrier head As a result, it is possible to reduce the possibility of wafer adsorption failure or adsorption failure, thereby preventing the wafer from falling off from the carrier head during wafer movement or wafer desorption, leading to scratching on the wafer pattern or breakage of the wafer. .

Description

Carrier Head for Chemical Mechanical Polishing

The present invention relates to a carrier head of a chemical mechanical polishing apparatus for polishing and planarizing a semiconductor wafer.

BACKGROUND A chemical mechanical polishing apparatus is a device for planarizing a wafer surface to reduce non-uniformity of the wafer surface caused by repetition of masking, etching, and wiring processes during semiconductor wafer manufacturing.

The carrier head used in the chemical mechanical polishing apparatus is a place where a wafer for polishing is attached before starting polishing for the polishing process, and also for accommodating the wafer during the polishing process due to the relative movement of the carrier head and the polishing pad. It is used to remove the polished wafer through the relative movement of the polishing pad and the carrier from the polishing pad for subsequent processing after polishing.

Representative of such a carrier head is disclosed in Korean Patent Laid-Open Publication No. 2000-71788.

The above technique forms a plurality of suction holes in the support plate constituting the substrate support assembly, and attaches a flexible membrane to the outer surface of the support plate, but protrudes downward in the membrane portion located at the edge of the support plate. The lip portion of the membrane is completely sealed at the edge of the wafer when the wafer is vacuum-adsorbed to the membrane through the adsorption hole by integrally forming the flexible lip portion.

However, the carrier head having the above structure may cause an adsorption error during the adsorption of the wafer because the vacuum pressure of the chamber delivered to the wafer is relatively small compared to the pressure delivered to the membrane. During the desorption process, the wafer may fall from the carrier head, leading to scratching on the wafer pattern or breakage of the wafer.

In addition, when the wafer is detached from the polishing pad after the completion of the polishing process and adhered to the carrier, it requires more adsorptive force to break the surface tension applied to the wafer due to the residual liquid or deionized water present on the polishing pad. Therefore, in order to create a desired vacuum pressure due to the characteristics of the carrier head of the conventional indirect vacuum structure, a vacuum must be applied after forming a completely closed space between the wafer and the membrane by applying a relatively large physical force to the flexible lip and the like. Excessive force may be applied and may damage the wafer.

The present invention has been made to solve the above conventional problems, the present invention has the following object.

SUMMARY OF THE INVENTION An object of the present invention is to provide a carrier head for attaching a wafer at a small pressure using a vacuum method directly to the carrier head and applying a uniform pressure to the wafer surface during polishing of the wafer so that the wafer surface is evenly polished.

Another object of the present invention is to provide a carrier head capable of determining whether a wafer is attached by directly reading a change in vacuum pressure of a vacuum pipe from a pressure regulating device without installing a wafer sensing device.

Another object of the present invention is to provide a carrier head capable of easily removing contaminants that penetrate the carrier head during the polishing of a wafer.

Another object of the present invention is to provide a carrier head capable of easily detaching a wafer from a polishing pad and attaching it to a carrier without causing damage to the wafer after completion of the polishing process.

The present invention provides a carrier head according to the present invention, the carrier housing is driven by a carrier drive shaft; Disposed on the lower portion of the carrier housing and capable of vertically descending, the lower surface of which provides a surface for mounting a wafer of a predetermined diameter, wherein an adjustment chamber is formed therein to adjust the pressure inside the adjustment chamber. A wafer support assembly capable of adsorbing or removing the wafer; The wafer support assembly may be moved in a vertical direction with respect to the bottom surface of the wafer support assembly. The wafer support assembly may be disposed outside the wafer support assembly so that the movement in the vertical direction is performed separately from the shanghai movement of the wafer support assembly. A retainer ring forming a receiving space of the wafer so that the wafer does not deviate from the lower surface of the support assembly; A conditioner ring disposed outside the retainer ring so as to be movable in a vertical direction with respect to the lower surface of the wafer support assembly, and the movement in the vertical direction is performed separately from the shandong of the wafer support assembly; ; And a loading chamber formed in a space defined by the carrier housing and the body to control a vertical position of the wafer support assembly.

In addition, the carrier head according to the present invention is connected to a pressure pipe having a pressure regulator attached to an adjustment chamber formed inside the wafer support assembly, thereby measuring the pressure of the pressure regulator on the lower surface of the wafer support assembly. It is characterized in that whether or not the wafer is adsorbed.

1 is a cross-sectional view of a carrier head according to the present invention, showing the carrier head in a no-load state.

2 shows a state immediately before the carrier head according to the present invention adsorbs a wafer.

3 shows a carrier head in a state of polishing a wafer in a carrier head according to the present invention.

Figure 4 shows the carrier head in a state of cleaning the polishing pad using the retainer ring in the carrier head according to the present invention.

Figure 5 shows a carrier head in a state in which the polishing pad is conditioned using conditioning in the carrier head according to the present invention.

<Code Description of Main Parts of Drawing>

10 carrier carrier 20 annular body

30 wafer support assembly 31 carrier plate

33: adjustment chamber 34: carrier film

40: loading chamber 50: ring housing

60: retainer ring assembly 61: retainer ring

70: conditioning ring assembly 71: conditioning

72: brush

Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view of a carrier head according to the present invention.

As shown in FIG. 1, the carrier head of the present invention includes a carrier housing 10, an annular body 20, a wafer support assembly 30, a loading chamber 40, a ring housing 50, and a retaining ring assembly 60. ), The conditioning assembly 70 is made.

The carrier housing 10 is fixed to a carrier drive shaft (not shown) by a rotation connecting member formed at a central portion of the upper surface thereof, and four air passages are formed therein for aerodynamic control of the carrier head. The carrier housing 10 may generally be circular in shape corresponding to the circular configuration of the wafer to be polished.

The annular body 20 is installed at the lower center of the carrier housing 10, the outer surface is formed in a cylindrical shape so that the wafer support assembly 30 to be described later can be raised and lowered vertically by the action of pneumatic, In addition, when the wafer support assembly 30 sags downward due to its own weight of the wafer support assembly 30 due to the protruding jaw 21 formed on the lower outer surface thereof, the lowest position of the wafer support assembly 30. Let's decide.

The wafer support assembly 30 is disposed below the carrier housing 10 and vertically movable by varying the pressure of the loading chamber 40 to be described later. The carrier plate 31, the carrier plate holder 32, The adjustment chamber 33, the carrier film 34, and the bladder clamp 35.

The carrier plate 31 is a lower part of the plurality of components constituting the wafer support assembly 30, and a plurality of air passages 36 are formed therein to adsorb or remove the wafer by the action of pneumatic pressure. It is.

The carrier plate holder 32 is disposed above the carrier plate 31 to accommodate the carrier plate 31, and therein an air reservoir through which a fluid can flow between the pressure pipe 39 and the adjustment chamber 33. The retainer ring assembly is formed when the retainer ring assembly 60, which will be described later, is formed to have a protrusion 38 formed on the outer lower surface of the furnace 37 to be described below. Let the bottom of (60) be determined.

The adjustment chamber 33 is formed in a space defined by the carrier plate holder 32 and the carrier plate 31, and absorbs the wafer to the carrier film 34 by varying the pressure inside the adjustment chamber 33. In addition, during polishing, pressure is applied to the back side of the wafer so that the wafer adheres to the polishing pad to prevent the back side of the wafer from slipping during the polishing operation and to evenly polish the wafer surface. A pressure regulator (not shown) having a function of a pressure gauge is attached to the pressure pipe 39 communicating with the adjustment chamber 33 to utilize the difference in the vacuum pressure depending on the presence or absence of a wafer by the pressure regulator. Thus, it is possible to monitor whether or not the wafer is absorbed by the carrier plate 31.

The carrier film 34 is disposed under the carrier plate 31 to prevent the wafer from being damaged when the wafer is adsorbed onto the carrier plate 31, and may be in communication with an air passage formed in the carrier plate 31. A hole is formed.

The bladder clamp 35 is an annular member disposed above the carrier plate holder 32 to fix one end of the bladder 45 to be described later, and a pressure pipe 39 and a carrier plate holder 32 therein. There is an air passage through which the fluid can flow.

The loading chamber 40 is formed in a space defined by the carrier housing 10 and the wafer support assembly 30 to apply a load, for example downward pressure, to the wafer support assembly 30. One end of the bladder 45 is fixed to the ring housing 50 described later by bolts, and the other end is fixed to the carrier plate holder 32 by the bladder clamp 35. The bladder 45 therefore seals the space between the carrier housing 10 and the wafer support assembly 30 to define the loading chamber 40. An external air source (not shown) may be connected to the loading chamber 40 by the air passage 11 to control the pressure of the loading chamber 40 and the vertical position of the wafer support assembly 30.

The ring housing 50 may be disposed outside the lower portion of the carrier housing 10 to accommodate the retaining ring assembly 60 and the conditioner assembly 70, which will be described later, and the retaining ring assembly 60 therein. Air passages 51 and 52 are formed to supply or discharge air to the conditionering assembly 70.

The retaining ring assembly 60 is disposed in the groove portion formed inside the lower surface of the ring housing 50 and includes a retaining ring 61, a retaining ring holder 62, and a retaining ring chamber 63.

The retaining ring 61 is made of a hard plastic or ceramic material, and is configured in an annular shape having a flat bottom surface. The retainer ring 61 is in contact with the polishing pad to form a receiving space of the wafer so that the wafer is not separated from the carrier plate 31, which is the receiving surface of the wafer, and the slurry is supplied to the wafer from the outer surface of the retainer ring 61. It has a plurality of grooves in order to facilitate this.

The retaining ring chamber 63 is formed in a space defined by the ring housing 50 and the retaining ring holder 62 to apply a load, for example a downward pressure, to the retaining ring assembly 60. The vertical position of the retaining ring assembly 60 can be controlled separately from the shanghai copper of the wafer support assembly 30 by varying the pressure within 63.

The conditioning ring assembly 70 is disposed in the groove formed on the outer side of the lower surface of the ring housing 50, the conditioning ring tube consisting of the conditioning ring 71, the conditioning holder 73, the conditioning chamber 74 and the flexible member It consists of 75.

The conditioner ring 71 is in direct contact with the polishing pad, and the lower surface is equipped with a brush 72 or diamond for conditioning the polishing pad. Conditioning of the polishing pad is carried out by applying a suitable contact force according to the type and surface property of the polishing pad, and the vertical movement is performed by the variable adjustment by the pneumatic pressure of the conditioning chamber 74 independently. Pad conditioning is possible.

The conditioning chamber 74 is formed in a space defined by the ring housing 50 and the conditioning holder 73 so as to apply a load, for example a downward pressure, to the conditioning assembly 70, and the conditioning chamber ( By varying the pressure in 74, the vertical position of the conditioning ring assembly 70 can be controlled separately from the shanghai copper of the wafer support assembly 30 or the retaining ring assembly 60.

An operation of the carrier head according to the present invention having the configuration as described above will be described with reference to FIGS. 1 to 4.

1 is a cross-sectional view of a carrier head according to the present invention, showing a state in which no pressure is applied to each component of the carrier head.

In Fig. 1, the carrier head is slumped down by the weight of each component, and the wafer support assembly 30 is determined by the protrusion jaw 21 and the bladder clamp 35 of the annular body 20. The retaining ring 61 is determined by the protrusion 38 of the carrier plate holder 32 and the lowest position is determined by the deflection of the conditioner ring tube 75.

2 shows a state immediately before the carrier head according to the present invention adsorbs the wafer.

In FIG. 2, in the carrier head according to the present invention, the retainer ring 61 and the conditioner ring 71 are raised to stand by to allow the wafer to stably approach the carrier film 34. At this time, the carrier plate 31 is positioned as it is in the lowest position to suck the wafer, the retaining ring 61 is raised to the pressure drop while the pressure fluid is discharged through the fluid line to the retaining chamber 63, the conditioner The ring 71 rises to the pressure drop as the pressure fluid is discharged through the fluid line to the conditioning chamber 74.

In the above state, the wafer is adsorbed to the carrier plate 31, and in order to adsorb the wafer to the carrier plate 31, first, a loading device (not shown) is placed below the carrier plate 31, and then the loading is performed. When the device rises close to the carrier plate 31, the wafer mounted on the loading device is moved in the process of adsorbing air through each of the air passages 31 formed in the adjustment chamber 33 and the carrier plate 31. The plate 31 is to be adsorbed. At this time, whether or not the wafer is stably adsorbed to the carrier plate 31 is determined by the pressure adjusting device attached to the pressure pipe 39. Can be monitored whether the wafer is adsorbed on the substrate, and when the wafer is completely adsorbed on the carrier plate 31, the loading device returns to its original position.

When the loading device is returned to its original position as described above, the platen (not shown) is raised to bring the wafer into contact with the polishing pad.

3 illustrates a carrier head in a state in which a wafer is adsorbed on the carrier head according to the present invention and the wafer is polished.

In FIG. 3, the wafer adsorbed to the carrier head is positioned on the same reference plane as the retaining ring 61 and the conditioner ring 71. In the above state, while the slurry required for polishing is supplied from a slurry source not shown, the wafer contacts the polishing pad to polish the wafer. During polishing, the wafer support assembly 30 is increased by increasing the pressure in the loading chamber 40. The quality of the polished surface can be further improved by applying a vertical downward force to the back surface of the wafer by increasing the pressure in the adjusting chamber 33 and applying a vertical downward force to the back surface of the wafer.

The retaining ring 61 is lowered because the pressure is increased while the pressure fluid is supplied into the retaining ring 63 to prevent the wafer from falling out of the carrier plate 31, and the conditioner ring 71 is also provided. As the pressure fluid is supplied into the conditioning chamber 74, the pressure is increased so that the pressure is lowered to condition the polishing pad.

When the polishing operation of the wafer is completed as described above, first, the pressure fluid inside the adjusting chamber 33 is discharged to the outside through the pressure pipe 39 so as to seat the wafer on the loading device again. ), And whether or not the wafer is stably adsorbed to the carrier plate 31 is determined by the pressure regulator attached to the pressure pipe 39, by using the difference in the vacuum pressure depending on the presence or absence of the wafer. Whether or not it is adsorbed by the plate 31 can be confirmed.

When the wafer is completely adsorbed on the carrier plate 31, the platen is lowered to secure a space for the loading device, wherein the carrier plate 31 is based on the weight of the wafer support assembly 30 including the same. Alternatively, the pressure is applied to the inside of the loading chamber 40 and lowered back to the lowest position, and the retaining ring 61 discharges the pressure fluid inside the retaining chamber 63 through the fluid line to lower the pressure. The conditioner ring 71 rises to the pressure drop while discharging the pressure fluid inside the conditioning chamber 74 through the fluid line.

The carrier head in the above state is as shown in FIG.

In order to discharge the wafer seated on the loading device to the outside, first, the loading device is placed at the bottom of the wafer, and then the loading device is brought up close to the wafer, and then a pressure fluid is supplied into the adjusting chamber 33 so that the wafer is carrier The plate 31 is removed from the plate 31 and placed in the loading device, and the loading device on which the wafer is seated is lowered and returned to its original position.

On the other hand, since the wafer is polished in contact with the polishing pad while receiving the slurry required for polishing, it is necessary to remove residues or slurry generated in the polishing pad during the polishing operation.

Figure 4 shows the carrier head in a state of cleaning the polishing pad using the retaining ring 61 and the conditioner ring 71 in the carrier head according to the present invention.

As shown in FIG. 4, the retainer ring 61 when cleaning the polishing pad by using the retainer ring 61 and the conditioner ring 71 increases the pressure in the retainer chamber 63. The lowering is brought into contact with the polishing pad to apply pressure to the polishing pad to draw out slurry, impurities, and the like penetrated into the pad, and the conditioner ring 71 is supplied with a pressure fluid supply inside the conditioning chamber 74. The conditioner ring 71 contacts the polishing pad outside the retainer ring 61 to remove slurry, impurities, and the like from the outside to perform pad cleaning.

Fig. 5 shows the carrier head in a state in which the polishing pad is conditioned using the conditioning ring 71 in the carrier head according to the present invention.

As shown in FIG. 5, when the pressure fluid in the loading chamber 40 and the retaining chamber 63 is discharged, the carrier plate 31 and the retaining ring 61 are maintained at the highest lifted position. When the pressure inside the conditioning chamber 74 is increased, the conditioner tube 75, which is a flexible material, is expanded, and the conditioner ring 71 is lowered to be in close contact with the polishing pad.

Therefore, in the above state, it is also possible to perform the conditioning operation of the polishing pad by contacting only the conditioner ring 71 with the polishing pad without performing the polishing operation.

As described above, since the carrier head of the chemical mechanical polishing apparatus of the present invention adsorbs the wafer by using a direct vacuum method, the wafer can be easily attached to the wafer support assembly with a small pressure, and the wafer is evenly polished on the wafer surface during polishing. Pressure can be applied to smoothly polish the wafer surface, and the pressure regulator attached to the pressure pipe makes it easy to check whether the wafer is adsorbed to the wafer support assembly by using the difference in the vacuum pressure with or without the wafer. As a result, it is possible to reduce the possibility of wafer adsorption failure or adsorption failure, thereby preventing the wafer from falling off from the carrier head during wafer movement or wafer desorption, leading to scratching on the wafer pattern or wafer breakage. .

In addition, the carrier head of the chemical mechanical polishing apparatus of the present invention discharges the pressure fluid inside the adjusting chamber to the outside through the pressure pipe after completion of the polishing process, so that the wafer is vacuum-adsorbed to the wafer support assembly. The wafer can also be easily removed from the polishing pad and attached to the wafer support assembly.

Claims (11)

A carrier housing 10 driven by a carrier drive shaft; A body 20 fixedly installed at the lower center of the carrier housing 10; Disposed below the carrier housing 10 to be capable of vertically descending along the outer surface of the body 20, the lower surface providing a surface for mounting a wafer of a predetermined diameter, and an adjustment chamber therein. A wafer support assembly 30 which forms a 33 to adsorb or remove the wafer by adjusting the pressure inside the adjustment chamber 33; The wafer support assembly 30 may be moved in a vertical direction with respect to the bottom surface of the wafer support assembly 30, and the movement in the vertical direction may be performed separately from the shanghai movement of the wafer support assembly 30. A retainer ring (61) disposed outside the bottom surface of the wafer support assembly (30) to form a receiving space of the wafer so that the wafer is not separated from the lower surface of the wafer support assembly (30); The retainer ring 61 is movable on the lower surface of the wafer support assembly 30 in a vertical direction with the lower surface of the wafer support assembly 30, and the movement in the vertical direction is performed separately from the vertical movement of the wafer support assembly 30. Conditioner ring (71) installed on the outside; And a loading chamber (40) formed in a space defined by the carrier housing (10) and the body (20) to control the vertical position of the wafer support assembly (30). delete delete The pressure chamber (39) to which the pressure regulator is attached is connected to the adjustment chamber (33), and the lower surface of the wafer support assembly (30) is measured by measuring the pressure of the pressure regulator. A carrier head, characterized in that it is possible to confirm whether or not the wafer has been adsorbed. The wafer support assembly (30) of claim 1, wherein the wafer support assembly (30) sags downward by its own weight when the wafer support assembly (30) sags downward. Carrier head, characterized in that the supporting means for determining the lowest position is provided. delete 2. The carrier head as claimed in claim 1, wherein the retaining ring (61) has a plurality of grooves in its lower surface to facilitate the supply of slurry to the wafer. delete delete The carrier head (1) according to claim 1, wherein the conditioner ring (71) is equipped with a brush (72) or diamond for conditioning the polishing pad on a lower surface thereof. The conditioner ring 71 according to claim 1, wherein the conditioner ring 71 forms a chamber 74 therein so as to vary the pressure in the chamber, so that the conditioner ring 71 is separate from the air conditioner of the wafer support assembly 30 or the retaining assembly 60. Carrier head, characterized in that the vertical position of the ring 71 can be controlled.